瓯江口海域夏秋季蟹类多样性分析

Analysis of crab diversity in the Oujiang river estuary during summer and autunm

利用2007年6月和9月瓯江口海域渔业资源调查资料，研究瓯江口海域蟹类种类组成和多样性的时空分布，探索地形地貌、海流等因素对蟹类多样性的影响。结果表明，在两次拖网调查中，共鉴定蟹类16种。日本好（Argyrosomus argentatus）是6月的主要优势种，三疣梭子蟹（Portunus trituberculatus）是9月的主要优势种。在瓯江口近岸水域，单个站位出现的种类并不多，但整个近岸0～10m水域内蟹类种类丰富。这与近岸、近岛水域在不同季节、不同站位生态环境多样化和差异化有一定的关系。在瓯江口外海，海底地势平坦，不同站位之间环境差异不大，也没有岛屿阻隔，使得各个站位种类较多且组成类似。单一优势种出现是导致外部和南部水域蟹类多样性（H＇）值较低的主要原因。瓯江冲淡水势力和不同水团交汇影响瓯江口海域蟹类种类和多样性的分布。

Based on the data from investigation of two oceanographic censuses in the Oujiang estuary during June and September of the year 2007, this paper studied the crab composition, spatial-temporal distribution and richness and diversity （H＇） involved in some impact factors such as background of topography and geomorphy, as well as water masses. Results showed that 16 species was identified among which Argyrosomus argentatus was main dominant species in June, and Portunus trituberculatus in September. In 0-10m coastal waters, lower species number in each station and abundant species in whole areas are incompatible. This is because the whole waters was broken into different niches by many islands. On the contrary, broad and flat topography in the outer of the investigation areas made water environmental variation reduced so that similar species composition and abundant species were occurred simultaneously. A single absolutely dominant species made lower crab H＇ value in the south or east-south areas. Seasonal and regional Oujiang dilute water and cross of different water masses were critical in the affection on the crab richness and diversity of this waters.